This disclosure relates to diesel engines, and, more particularly, to a system and process for detecting conditions indicative of substandard performance of the cylinders, pumps, valves, and fuel injection devices within large scale multi-cylinder engines.
Spark ignition engines are internal combustion devices in which electrical discharges ignite air/fuel mixtures. One such spark ignition engine is an Otto cycle engine in which heat is converted to work in a thermodynamic cycle comprising alternating isentropic compressions and expansions of air/fuel mixtures interspersed with alternating additions and rejections of heat at constant volume. Compression ignition engines, on the other hand, are internal combustion devices in which high compression ratios produce the ignition of air/fuel mixtures. One such compression ignition engine operates under a diesel cycle, in which the air/fuel mixture is ignited under a compressive force. In a diesel cycle engine, heat is converted to work via alternating isentropic compressions and expansions of air/fuel mixtures interspersed with alternating heat additions at constant pressure and heat rejections at constant volume. The conventional ignition processes of spark ignition engines are inapplicable with respect to diesel engines.
For either type of engine, control of the engine is attained primarily through the influence of a fuel injection or delivery process and the amount of fuel injected. Differences in tolerances of the components of an engine oftentimes result in variation in the behavior of each of the individual cylinders of the engine. This variation causes less than optimum performance to be realized by the engine. Such performance is characterized by low power output as a result of weak or non-functional cylinders, fuel pumps, and/or fuel injection devices. Operation of the engine on a weak or non-functional cylinder generally results in increased fuel consumption, emission of harmful substances, vibration, excessive noise, and shortened service life.
While increased fuel consumption, emission of harmful substances, vibration, excessive noise, and shortened service life are generally indicative of a weak cylinder condition, such indicators require lengthy periods of monitoring of a large number of attributes of the engine. Direct methods of the detection of weak and non-functioning cylinders have been performed by highly skilled artisans using solely their experience-trained senses. In these methods, an operator of an engine brings the engine up to a load and a speed and allows the engine to reach a steady state condition. The operator then monitors the fuel volume flowing from one of the fuel pumps or injectors to one of the cylinders. For each cylinder, the skilled operator listens to the sound emanating from the cylinder and makes a determination regarding the response of the cylinder to the changed volume of fuel being supplied. Given even a narrow range of environmental and other conditions, such a determination is generally highly subjective and open to various interpretations even by the same operator. Some interpretations may result in the removal of trouble-free cylinders, pumps, or injectors, particularly if communication across the cylinder, pump, or injector is intermittent for any reason (e.g., the cylinder, pump, or injector experiences an “open stator” condition). In such a case, the lack of electrical communication may cause normally functioning cylinders, pumps, or injectors to misfire, thereby giving false test results and leading to unnecessary removal of such devices. Based on the determination itself, the operator makes a judgment as to the condition of the components of each cylinder and thereby recommends remedial or other action.
While such methods have been effective for many years, they are not the most economical, effective, or accurate means of determining the condition of the cylinder structures of internal combustion engines. Furthermore, they are certainly not the most time-efficient methods or a means that can be carried out with the frequency required by the operation of large scale equipment into which an engine is incorporated.